1. Field of the Invention
The presentation information 120 includes style information used to render the subtitle texts and comprises a plurality of style groups. A style group is a bundle of styles in which the style information is recorded. A style includes information used to render and display a subtitle text. This information includes, for example, one or more of a style name, a font, a text color, a background color, a text size, a line-height, a text output region, a text output start position, an output direction, or an alignment method.
2. Description of the Related Art
A conventional subtitle is a bitmap image that is included in an audio-visual (AV) stream. Therefore, it is inconvenient to produce such a subtitle, and there is no choice but to merely read the subtitle in its present form without modification since a user cannot select various attributes of the subtitle defined by a subtitle producer. That is, since the attributes, such as font, character size, and character color, are predetermined and included in the AV stream as a bitmap image, the user cannot change the attributes at will.
Also, since the subtitle is compressed and encoded in the AV stream, an output start time and an output end time of the subtitle are clearly designated to correspond to the AV stream, and reproduction times when subtitles are output should not overlap. That is, only one subtitle should be output at a certain time.
However, since an output start time and an output end time of a subtitle are designated by a subtitle producer and recorded on an information storage medium separately from the AV stream, the output start times and output end times of a plurality of subtitles may overlap one another. In other words, since more than two subtitles may be output in a certain time period, a method of solving this problem is necessary.